1. Field of the Invention
The present invention relates to a display control apparatus and a display control method, and more particularly, to a display control apparatus and a display control method which are preferred for use in a video display apparatus which is able to simultaneously display multiple videos on one screen.
2. Description of the Related Art
Recently, image quality adjustment functions for higher image qualities, such as a noise reduction function, a gamma correction function, and a color tone correction function, have been mounted for many video display apparatuses such as TV receivers. In order to adjust individual parameters appropriately for these functions, a relatively sophisticated understanding of image characteristics is required. Therefore, it is common to preset, at shipping, some sets of parameters in accordance with the genre of video content or the like. The user can obtain videos with image qualities in accordance with purposes of watching, by a simple operation of selecting a set of preset parameters.
As one of such sets of parameters, there is a dynamic mode. In the dynamic mode, each parameter is adaptively varied in response to the characteristics of a video being displayed. As one example, when a video has high brightness over the entire screen, it is conceivable to set parameters so as to reduce the brightness and decrease the gamma correction value. Alternatively, when a video is dark with low brightness over the entire screen, it is conceivable to set parameters so as to increase the gamma correction value and enhance the contrast, and further to increase the color saturation. Adaptively carrying out such parameter control depending on video display allows the user to watch even videos which vary significantly in brightness or color shade in a time series manner, always at easily viewable image quality.
Furthermore, recent TV receivers primarily include models including a plurality of external input terminals for inputting moving image data or still image data. Some of such models allow videos of moving image data or still image data output from external devices connected to the plurality of external input terminals to be displayed simultaneously. For example, zooming is carried out, if necessary, for each piece of moving image data or still image data supplied from the plurality of external image input terminals, and the pieces of data are arranged in predetermined positions to be synthesized in one frame and displayed on a screen.
Now, consider a case of executing the dynamic mode described above and displaying a plurality of videos and images simultaneously on one screen. As one example, it is assumed that a video A (a video mainly including a person under illumination) and a video B (a video including a night view) which are completely different in terms of content are to be simultaneously displayed on one screen. In a case in which the dynamic mode is executed for this screen, image quality adjustment in accordance with the dynamic mode will be carried out for the entire screen including the video A and the video B. More specifically, the image quality adjustment carried out at this point is not specified for the video A or the video B. Therefore, there is a possibility that this image quality adjustment is not suitable for either the video A or the video B.
Japanese Patent Laid-Open No. 2003-348488 discloses a technique for exercising luminance control for display on the basis of luminance information of an image source rendered in the largest size, in the case of displaying multiple videos or images of a main video or image and a secondary video or image. According to Japanese Patent Laid-Open No. 2003-348488, the technique is useful in a case in which the video or image watched by the user with attention is the largest video or image of the multiple videos or images.
However, the technique described in Japanese Patent Laid-Open No. 2003-348488 has problems as described below.
Japanese Patent Laid-Open No. 2003-348488 is useful if the user watches with attention the video or image with the largest display size out of multiple screens displayed on one screen as described above. However, the user does not necessarily watch with attention the video or image with the largest display size, and this case has a problem in that there is a possibility that image quality adjustment expected by the user will not be carried out. For example, in a case in which the original display size of the video or image to be watched with attention is smaller than the other video(s) or image(s), the video or image will not be a target of image quality adjustment in accordance with the dynamic mode.